I replaced my right rear brake caliper and pads less than three months ago. they seemed fine but just today I heard an almost metallic squeak that would only happen during moderate braking and it's not a constant squeak. the only thing I could think of is that the rotor is warped but I haven't really done anything that would warp it. I'm also pretty sure it doesn't occur when wet because I've washed it and it's rained after installation and this hasn't occured.

 

Nobody can give just a little advice or know how????

 

I was going to say you need brake lube on the edges of the shoes, but then I realized you said calipers, indicating you have rear discs...Maybe you need to lube the pins?

 

resurface your brake